This application claims priority from Korean Patent Application No. 2003-87166, filed on Dec. 3, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a polynucleotide microarray including polynucleotides which are immobilized according to a melting temperature (Tm) and a method for detecting target polynucleotides using the same.
2. Description of the Related Art
A microarray is well known in the pertinent art. Examples of the microarray are disclosed in U.S. Pat. Nos. 5,445,934 and 5,744,305. A method of fabricating a microarray using photolithography is generally known. According to a method of fabricating a polynucleotide microarray using photolithography, predetermined regions of a substrate coated with a monomer having a removable protecting group are exposed to an energy source to remove the protecting group. Then, the deprotected monomer is coupled with a monomer having a removable protecting group. Repetition of the above processes produces a polynucleotide microarray. In this case, polynucleotides to be immobilized on the polynucleotide microarray can be prepared by continued extension of polynucleotide monomers. Alternatively, previously synthesized polynucleotides can be immobilized on predetermined regions of the polynucleotide microarray (also called as “spotting technique”). Such fabrication methods for polynucleotide microarrays are illustrated in U.S. Pat. Nos. 5,744,305, 5,143,854, and 5,424,186. The above patent documents about polynucleotide microarrays and fabrication method thereof are incorporated herein in their entireties by reference.
However, probe polynucleotides are randomly immobilized on these conventional polynucleotide microarrays. Furthermore, a single microarray is covered with a cover formed with an inlet and an outlet for a single hybridization solution, and thus, only single hybridization reaction is allowed. Therefore, conventional microarray techniques are silent about immobilization of probe polynucleotides according to Tm and polynucleotide microarrays including a plurality of blocks.
Various methods for detecting target polynucleotides are known. Generally, according to these methods, target polynucleotides are labeled with a detectable marker and then hybridized with probe polynucleotides on a polynucleotide microarray. After the hybridization is completed, the result of hybridization is analyzed. For example, U.S. Pat. No. 5,871,928 discloses a method for detecting hybridization between target polynucleotides and probe polynucleotides, which includes: (a) attaching labels to the target polynucleotides, (b) contacting, under hybridization conditions, the labeled target polynucleotides with a collection of the probe polynucleotides immobilized on known regions of a substrate; and (c) determining the sequences of the probe polynucleotides which hybridize with the target polynucleotides, the collection including at least 100 probes/cm2.
According to the above method, the collection of the probe polynucleotides immobilized on the microarray is used. However, there is no mention about a method of using blocks of immobilized probe polynucleotides that are grouped according to Tm between the probe polynucleotides and target polynucleotides.